Mobile communications, including cellular communications, involve the transfer of data or information. Various bandwidths or bands of a spectrum are used for communication. These bands can be licensed or otherwise allocated for communication between mobile devices and base stations.
Typically, bands are allocated for use by only specific or authorized devices. This allocation, referred to as licensing, attempts to prevent issues such as cross talk, interference, noise and the like from degrading mobile communications. Only authorized devices can use the band, so the channels or bands are clear for communication.
However, portions of the spectrum or bands can remain unused for various reasons. It could be that a licensee isn't operating at the time. It could also be that the band is reserved for a purpose, but is not needed. This lack of use of spectrum, which is available, degrades mobile communications.